Forum for Science, Industry and Business

No logical thinking required: causality judgments can be „felt“

11.01.2013

We often make causality judgments when we perceive successive visual events, such as “the glass was knocked over by the hand“.

A research team led by Martin Rolfs at the Bernstein Center and Humboldt University Berlin, has now revealed that these judgments arise from fundamental visual processes – without involving higher cognitive reasoning. They showed that, with prolonged viewing of causal events, an adaptation process takes place that resembles those observed in the perception of size, color, or motion of an object. The result ends a long-standing debate about the level at which higher-order properties of visual events are computed.

The hand hits a glass, it falls over, and the milk spills over the kitchen table. The observer is immediately sure that it was the clumsy hand that caused this little mishap. Until now, researchers have disagreed whether this causality judgment depends on higher brain functions such as cognitive reasoning, or whether it emerges at an earlier stage during perception, similar to the evaluation of size, color, or motion of an object. An international team of researchers including Martin Rolfs at the Bernstein Center Berlin, Michael Dambacher at the University of Konstanz, and professor Patrick Cavanagh at the University Paris Descartes has now found the answer to this question: Rapid causality judgments are made at the level of visual perception.

In their study, participants watched a repeating video clip in which one disc moved towards another, and the latter disc started to move after being touched by the first. Instead of seeing one disc stopping and the next disc starting to move, both events are seen as one continuous action where the first disc launches the second – similar to colliding billiard balls. Rolfs and his colleagues have now demonstrated that after the repeated observation of these collision scenes, an adaption process occurs: Subsequent interactions involving two discs are less likely to be seen as causal. Similar adaptation aftereffects are known after the repeated perception of basic properties such as color: After looking at an orange light for a short while, you will see a light blue spot when looking at a white wall. These visual aftereffects suggest a habituation of the populations of neurons in those parts of the brain that analyze these specific qualities.

The main result of the study: The adaptation to collision events was specific to the location where the collisions had been seen. Moreover, when the eyes moved, these adapted locations moved with the eyes, just as the color afterimage shifts as you move the eyes around. According to the researchers, these results show that the neuronal structures involved in the judgment of causality must be part of the early visual process as higher level cognitive processes do not show this specificity to eye position. Main investigator Rolfs: “The result moves functions that have previously been thought of as achievements of cognitive deduction into the realm of basic perception, with implications for fields as diverse as philosophy, psychology, and robotics.”

The Bernstein Center Berlin is part of the National Bernstein Network Computational Neuroscience in Germany. With this funding initiative, the German Federal Ministry of Education and Research (BMBF) supports the new discipline of Computational Neuroscience since 2004 with over 170 Mio. €. The network is named after the German physiologist Julius Bernstein (1835-1017).

Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.

It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:

The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.

One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...